The present invention relates to a seat slide device for a vehicle and, more particularly, a structure for movably supporting an upper rail with respect to a lower rail.
Japanese Laid-Open Patent Publication No. 10-315810 discloses a seat slide device for a vehicle. In the device, a slider having a plastic projection is attached to an upper rail. The upper rail elastically presses the slider against a lower rail when moving. This prevents rattling of the upper rail with respect to the lower rail when the upper rail moves.
However, in the device described in the aforementioned document, the plastic projection is constantly pressed against the lower rail. As a result, even if the upper rail is unlocked from the lower rail, resistance to movement of the upper rail may easily occur. Also, errors in dimensional accuracy may occur between the lower rail and the upper rail. In this case, elastic force produced by the plastic projection changes easily and thus increases the resistance to movement of the upper rail to an excessive extent. This can hamper operation for moving the upper rail. Further, when the upper rail is locked with respect to the lower rail, errors in dimensional accuracy between the upper rail and the lower rail may cause the plastic projection to contact or separate from the lower rail. As a result, the upper rail is likely to rattle with respect to the lower rail.